Implemented enhancements:
- Complete messages and message types APIs #66
- Complete comments api #65
Merged pull requests:
- Refactor check for valid basecamp url #67
- Bump rspec from 3.9.0 to 3.10.0 #64
- Rewrite API modules to use module nesting #63
- Bump rubocop from 1.0.0 to 1.1.0 #48
